Python (OOP) list append error

Question

in need of a little insight. I have the following python code:

>>> class invader:
...     def __init__(self):
                // list
...             self.parameters = []
...
...     def parameters(self):
...             param = self.parameters
...             param.append('3')
... 
>>> invade = invader()
>>> invade.parameters()

Running this in terminal produces the following error message:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'list' object is not callable

How can I solve this?

Don't use parameters as both a member and property name.

nicolas
– nicolas

2015-07-02 22:58:41 +00:00
Commented Jul 2, 2015 at 22:58 — nicolas
– nicolas, Commented Jul 2, 2015 at 22:58

Padraic Cunningham · Accepted Answer · 2015-07-02 23:05:59Z

3

You problem is using the same name for your attribute and method, rename self.parameters to self.param and use self.param in your method:

class invader:
   def __init__(self):
     self.param = []

   def parameters(self):
      self.param.append('3')

invade = invader()
invade.parameters()
print(invade.param)

answered Jul 2, 2015 at 23:05

Padraic Cunningham

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Comments

Anthony Kong · Accepted Answer · 2015-07-02 22:59:30Z

1

In the last line:

invade.parameters()

You are effectively using the list parameters as a function. (Note () at the end)

Do a

print invade.parameters

will let you see the content of the list and remove the runtime error

answered Jul 2, 2015 at 22:59

Anthony Kong

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Comments

Malik Brahimi · Accepted Answer · 2015-07-02 23:15:58Z

1

Both your method and attribute contain the same name parameters so you can do as follows here:

def parameters(self):
    self._parameters.append('3')

It's a common to encapsulate attributes with underscores, especially with methods of the same name.

answered Jul 2, 2015 at 23:15

Malik Brahimi

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flingjie · Accepted Answer · 2015-07-03 00:02:56Z

0

Your method and attribute contain the same name parameters. Since data attributes will override method attributes with the same name. So invade.parameters is list, not function. You should rename your function, such as append_parameters.
If you want to call parameters function, you can try this way:invader.parameters(invade).But it's not recommended

answered Jul 3, 2015 at 0:02

flingjie

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